The AVO exposure
meter was made by the catchily named Automatic Coil Winder And Electrical
Equipment Company Limited. Not content with shortening it to memorable
ACWAEEC the company wisely used AVO (Amps, Volts and Ohms) as their trade
mark. They were by far the most prominent manufacturer of general electrical
measuring instruments in the UK for many year and their multi-meters were
recognised as the best by professionals - until digital meters replaced
moving-coil meters. The meters you see here were their venture into the
lucrative exposure meter field dominated by their rivals Weston who were
also into electrical measurement meters.

The two meters
shown are varients of model - the sligtly newer meter (on the right) has an
easier to use dial. As you can see, the meter is quite deep and has a large
selenium cell deeply recessed into the front. It's aiming accuracy is enhanced
by two internal baffles.

The meter has
only one sensitivity range but is surprisingly sensitive. The black pointer
is aligned with the red needle by turning the dial, and the exposure read
off. Speeds are in the H&D scale (Hurter and Driffield) from 200 to 5000.

The meter originally
came in a leather case. One was bought at a boot sale for £6 and the
other on ebay for £6.50.

We don't have
a date for this meter but the art deco style of the lettering suggests 1930s.

This is a Metrovick meter, made by the Manchester based Metropolitan Vickers Company from 1938 until at least 1947. The main dial is set so that with 23 Schneider
rated film and f8, the shutter speeds can be directly read off. The calculator,
which was part of the leather case, allowed other aperture/film speed combinations
to be used. Although very old, this meter is still working and accurate enough
to be used.